Particle accelerator



Nov. 8, 1960 v. A. CAMPANILE 2,959,700

marrow ACCELERATOR Fil ed Nov. 24, 1958 24 25 v v 23 I I 22 16 r j 35 as30 FIG I FIG. 2

INVENTOR; VINCENT A. CAMPANILE HIS ATTORNEY United States Patent C MPARTICLE ACCELERATOR Vincent A. Campanile, San Lorenzo, Califi,assignor' to Shell Oil Company, a corporation of Delaware Filed Nov. 24,1958, Ser. No. 775,966

4 Claims. (Cl. 313-64) This invention pertains to particle acceleratorsand more particularly to a means for rapidly obtaining different typesof radiation from a particle accelerator.

A considerable amount of the research being performed today utilizes aparticle accelerator as a source of charged particles such as electrons,positive ions, X-rays, gamma rays, neutrons and the like. Twocommonly-used accelerators are the Van de Graaff generator and thelinear accelerator. In both of these accelerators a beam of electrons isaccelerated to a high velocity and directed through a beam tube so thatit will pass through a window or impinge upon a target positioned overthe exit of the scanning section of the beam tube. When .it is desiredto produce a beam of electrons the electron beamxIo-f. the acceleratoris passed through an aluminum window while if X-rays are to be producedthe'electron-beam vof.the accelerator is made to'impinge on a goldtarget. Presently-used accelerators require that in order tochangefromIan electron beam to an X-ray beam one must remove the aluminumwindow and replace it with a gold target ,and're-establish the vacuum inthe scanning section of the beam tube of the accelerator. There-establishing of the vacuum in the beam tube is a relatively longprocess due to the high vacuum required, thus the total time requiredto'change accelerators from one type of radiation to another is a fewhours which means that the accelerator is quite inflexible. theaccelerator is particularly bad in those situations where theaccelerator is used to perform basic research since very seldomdoconsecutive experiments require the same type of radiation;

I: Accordingly, his the primary object of this invention to provide ameans for rapidly changing the character of the energy beam of aparticle accelerator.

A further object of this invention is to provide a means for rapidlychanging the character of the energy beam of a particle acceleratorhaving a scanning tube sectionby positioning various types of windows ortargets in line with the beam tube of the accelerator.

A still further object of this invention is to provide a particleaccelerator with a scanning tube section having a plurality of chambersin order that a plurality of windows or targets may be positioned belowthe exit of the scanning tube section.

A still further object of this invention is to provide a particleaccelerator with a scanning tube section one end of which is bothpivotally and hermetically secured to the exit end of the beam tube ofthe accelerator and whose other end is provided with a plurality offlanged openings. Various scanning windows or targets may behermetically attached to the flanged openings in order that the beamtube may be rotated about its pivoted end to selectively align one ofthe scanning windows or targets with the axis of the beam tube.

The above objects of this invention are achieved by providing a particleaccelerator with a scanning tube section one end of which is pivotallyconnected to the beam tube and the other end of which is provided with aplu- This inflexibility of Patented Nov. 8, [1960 ICC rality of flangedopenings to which various scanning windows ortargets may be attached. Inaddition to being pivotally connected to the beam tube the scanning tubesection is hermetically sealed to the beam tube and each of the flangedopenings in the other end are hermetically closed by a scanning windowor target. In order to align various scanning windows or targets withthe axis of the beam tube all that is necessary is to rotate thescanning tube section about its pivot which in turn will bring adifierent scanning window or target into alignment with the axis of thebeam tube.

The above and other objects of this invention will be more easilyunderstood by those skilled in the art from the following description ofa preferred embodiment when taken in conjunction with the attacheddrawing in which:

Figure 1 is a front view of a portion of the beam tube of theaccelerator with the scanning tube section of this invention attachedthereto;

Figure 2 is an end view of the scanning tube section shown in Figure 1;

Figure 3 is a horizontal section taken along the line 3--3 of thescanning tube section; and

' Figure 4 is a bottom view of the scanning tube section taken along theline 44 of' Figure l'.

Referring to Figures 1, 2, 3, and 4, there is shown a scanning tubesection 10 which is pivotally and hermetically' fastened to the lowerend 12 of the beam tube 11 of the particle accelerator. The particleaccelerator may be. either a Van de Graatf generator or a linearaccelerator or'any other accelerator which produces a beam of electronsand discharges them through a beam tubes The scanningtube section 10consists of a flared tubular section having an oblong cross section asshown in Figure 3, preferably formed of a relatively light materialhaving substantially no interaction with electrons such as aluminum orthe like. In order to permit the -'tubular section 13 to be formed ofrelatively thin material suitable stiffening members 14 and 15 areattached to the flat sides of the lower portion of the tubular member toincrease its rigidity. A flange 16 is secured to the upper end of thetube section 13 by any desired means such as welding or the like. Asimilar flange or plate member 22 is secured to the lower end 12 on beamtube 11. The opposite ends of a bellows 20 are hermetically sealed tothe flange members 16 and 21 by any desired means such as welding or thelike. The opposite ends ofthe bellows 20 may be provided with flangessimilar to the flanges 16 and 22 with the flanges being hermeticallysecured to the flanges 16 and 22 by means of bolts and gaskets.

Two diametrically opposed ears or lug-type members 23 are secured to theouteredge of the flange 16 by any desired means such as welding or thelike. Two similar ears or lugs 24 are secured to the flange 21 bywelding or the like and are positioned so that they overlap the ears 23.A pivot pin or bolt 25 passes through holes formed in the overlapportions of the two ears 23 and 24 thus forming a hinged joint havinglimited movement between scanner tube section 10 and the beam tube 11.The pivot pin 25 should be a relatively tight fit in the openings in thecars 23 and 24 to eliminate all unnecessary clearance in this hingedjoint and insure accurate alignment of the scanning tube section withthe beam tube of the accelerator.

The lower end of the tube section 13 is provided with two oblong-shapedflange members 30 and 31. These flanged members may be attached to thetube section 13 by any desired means such as welding or the like and inaddition may be formed from a single member if desired. Each of theflanged members 30 and 31 are provided with a plurality of tapped holes34 in order that a variety of scanning windows 36 and 37 may be securedto the flanged openings by use of machine screws 35. Of course,

in the scanning tube section.

suitablelprecautions must be taken to insure a hermetical seal betweenthe scanning windows and the flanges in order to permit one to obtainthe high vacuum necessary The plane of the flange members 30 and31'should besubstantially perpendicular to the axis of each half of thescaningtube section 12 as seen in Figure 2.

Two clips'or ears 40 are attached by welding orthe like to the oppositeside walls of the tubular section 13 as shown in Figures 1 and 2.Rod'members 41 which are provided with a forked-end 42 at one end areconnected to the clips 40 by passing a toggle pin 43 or the like throughan'opening in the clips and similaropenings in the forked end 42 of therods "41. The opposite ends of the rods 41 not shown inFigures l and 2are secured to any structure surrounding the particle acceleratorbymeans of toggle pins or the like in order to maintain the scanningtube'section in a predetermined fixed position. Of course when'itis'desired to reposition the scanning tube section to align adiflerent'scanning window with the axis of the beam tube, rods havingdifferent lengths will berequircd. The same rods may be used for allpositions of the scanning tube section if suitable provisions are madefor adjusting their length. Likewise, other means may be used to lockthe scanning tube section in each position.

When the above-described scanningtube section is attached to a beam tubeof a particle accelerator all that is required to align a differentscanning window or target with the axis of the beam tube is to rotatethe beam tube section about the hinge joint 25 and lock it in positionby installing the proper length rods 41.

While but one embodiment of this invention has been described in detail,many modifications and changeswill occur to those skilled in the art.

I claim as my invention:

1. A scanner section for adapting a particle accelerator to selectivelyproduce a plurality of different types of charged particles comprising:a flared tubular scanner section, the'small end of said scanner'sectionbeing hermetically sealed to the end of the beam tube of theaccelerator; pivot means adjacent said small end of the scanner section,said pivot means being disposed topermit rotation of the other end ofsaid scanner section about an axis substantially perpendicular to theaxis of the beam tube of the accelerator; a plurality of flange openingsformed on the large end of the scanner section, the place of each ofsaid flanged openings being substantially parallel to the axis of thepivot means; securing means for securing said. scanner section in aplurality of predetermined positions, each of said predeterminedpositions'being disposed to align the plane one of said flanged openingssubstantially perpendicular to the axis of a beam tube of theaccelerator; and a different type .of scanning windowffor hermeticallyclosing each of said flanged openings.

2. A scanner tube for adapting a particle accelerator to selectivelyproduce a plurality of diflerent types of charged particles comprising:a scanning tube, said scanning tube being hermetically sealed to thebeam tube of the accelerator; means hermetically disposed on the exitend of said scanning tube for forming a plurality of discharge openings;a difierent type of scanning window hermetically secured to eachdischarge opening and means for physically moving said scanning tube toselectively align said discharge openings with the axis of said beamtube.

3. A scanning tube for adapting a particle accelerator to selectivelyproduce a pluralityof different types of charged particles comprising: aflared tubular scanning member; a bellows member, one end of saidbellows member being hermetically sealed to the small end of saidscanning member, the other end of the bellows member being hermeticallysealed to the end of the beam tube of the accelerator; hinge means forfastening said scanning member to said beam tube, the axis of said hingemeans being substantially perpendicular to the axis of the beam tube; aplurality of flanged openings formed in the other end of said scanningmember, the planes of said openings being parallel to the axis of saidhinge means in one direction and at an angle to the axis of the scanningmember in another direction; a plurality of different scanning windowsfor hermetically closing said flanged openings; and securing means forsecuring said scanner member in a plurality of predetermined positions,each of said predetermined positions being disposed to perpendicularlyalign the plane one of said flanged openings with the axis of the beamtube.

4. A scanning tube for adapting a particle accelerator toselectivelyproduce a plurality of different types of charged particles comprising:a tubular member secured to the beam tube of the accelerator, saidtubular member having a plurality of openings at its exit end; adifferent type of scanning window hermetically secured to each openingand mechanical means for moving the tubular member to selectively directthe beam of the accelerator through a predetermined one of saidopenings.

References Cited in the file of this patent UNITED STATES PATENTS2,298,335 Atlee Oct. 13,1940. 2,389,935 Rothstein Nov. 27, 19452,437,418 Cawein .Mar. 9, 1948 2,511,853 Kaiser June '20, 1950 2,637,818Gund et al May.5, 1953 2,722,620 Gale Nov. :1, 1955 2,887,583 EmanuelsonMay 19, 1959 FOREIGN PATENTS 202,962 Australia Aug. 2, 11956

